Numerical and experimental investigations on the modification of as-welded residual stress after local material removal

The detailed procedures of experiments and numerical simulations to investigate the modification of as-welded stress after milling a local region from the welded plate are presented. A three-dimensional (3D) finite element model was employed to simulate the residual stress induced by multi-pass welding. Taking the as-welded residual stress as the initial stress state, the stress modification of as-welded stress by local material removal with a mill process was also numerically investigated. A welding experiment, milling process, and stress measurements were carried out to validate the numerical analysis. The local material removal with a milling process was considered as a simple stress relief process during the finite element simulation, which was validated by the experimental results. With the proposed numerical model, the modification of as-welded through-thickness stress owing to local material removal was discussed. Investigated results showed that less local material removal does not seem significantly to influence the stress distribution and magnitude at the weld centreline; by increasing the thickness of the material removal, the through-thickness transverse stress within the weld zone changed more noticeably than the through-thickness longitudinal stress, while within the region far from the weld seam, the through-thickness longitudinal stress largely increased, as opposed to the through-thickness transverse stress, which changed little.